Magnetic Fishing Tool with Alternative Flow Capability and Method

ABSTRACT

The magnetic fishing tool has an axial flow passage through a valve member and one or more magnets for initial dispersal of debris away from the fish. Once engaged to the fish the flow direction can be altered by moving the valve member to open lateral ports and to close the straight through path so that fluid circulates above the fish to clear debris from ahead of the fish on the trip out of the hole. This can be accomplished with an object landed on a seat in the valve member, which causes it to shift axially to expose the lateral ports. Optionally the valve member can be shifted with flow in which case the flow will continue axially as well as laterally for the retrieval of the fish.

FIELD OF THE INVENTION

The field of the invention is magnetic fishing tools and related methodsand more particularly where the flow can be directed down to the fishand then redirected for circulation above the magnet during retrieval ofthe fish.

BACKGROUND OF THE INVENTION

At times magnetic objects need to be removed from a borehole in aprocess called fishing. These operations typically involve fluidmovement for debris agitation around the object to be retrieved known asthe fish. Magnets are used to bring a connection close to the fish withthe hope of engaging the fish in a way that will allow it to be pulledout of the hole and retained for the trip up the hole to the surface.Other applications simply use magnets to capture debris loosened bycleaning devices. These designs are illustrated in U.S. Pat. No.5,348,086; US20130000884; U.S. Pat. Nos. 8,689,877; 6,357,539 (FIG. 7);U.S. Pat. Nos. 6,629,562; 3,905,631 and 4,059,155.

One issue with the prior designs is that they either lacked acirculation path altogether or their circulation path was exclusivelydownwardly oriented toward the fish. The idea was to disperse debris tofacilitate dispersal of debris around the fish to enhance the chance ofgrabbing the fish for the trip out of the hole. The flow regime wasalways deployed in a single direction and this allowed the suspendeddebris to settle back down as the fish removal was attempted. Thepresent invention addresses this shortcoming in the prior design byallowing the flow direction to be changed from the time up to engagementof the fish until the time it is desired to bring out the fish. The flowdirection is changed from straight down toward the fish to laterally oruphole orientation to disperse or fluidize debris ahead of the fish toenhance the removal of the fish and minimize the chance of getting thefish stuck on the way out of the hole. To make this happen a flowthrough valve member is positioned to block lateral or uphole flow untilthe fish is engaged. Thereafter, the valve member can be activated withhigher flow or a dropped object on a seat to shift the valve member andopen ports that will direct flow laterally or in an uphole direction toaid the removal process for the fish. These and other aspects of thepresent invention will be more readily apparent to those skilled in theart from a review of the description of the preferred embodiment and theassociated drawings with the understanding that the full scope of theinvention is to be determined from the appended claims.

SUMMARY OF THE INVENTION

The magnetic fishing tool has an axial flow passage through a valvemember and one or more magnets for initial dispersal of debris away fromthe fish. Once engaged to the fish the flow direction can be altered bymoving the valve member to open lateral ports and to close the straightthrough path so that fluid circulates above the fish to clear debrisfrom ahead of the fish on the trip out of the hole. This can beaccomplished with an object landed on a seat in the valve member, whichcauses it to shift axially to expose the lateral ports. Optionally thevalve member can be shifted with flow in which case the flow willcontinue axially as well as laterally for the retrieval of the fish.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of the magnetic fishing tool with a protectivecover for shipping;

FIG. 2 is an enlarged view of the circle shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a fishing tool body 10 having an upper connection thread 12and a lower end open recess 14 in which resides at least one magnet 16.A passage 18 extends from thread 12 to recess 14. A sleeve 20 has apassage 22 and outer peripheral seals 24 against the body 10 in thepassage 18. Flow entering passage 18 continues through passage 22 andout recess 14 past the magnet or magnets 16 when running in the holetoward the fish, not shown, that is to be retrieved. Also shown in FIG.1 is a protective cover 26 with handles 28 that is removed before thebody 10 is run in the hole on a variety of conveyances that are notshown. Such conveyances can be rigid or coiled tubing, for example, sothat pressurized fluid can be delivered through passages 18 and 22 onthe way to the fish.

During running in the lateral ports 30, three of which are visible inthe section view of FIG. 1, are closed as they are located between sealassemblies 32 and 34. While the ports 30 are shown at 90 degrees to theaxis of body 10 the ports can be tilted in an uphole direction or theycan be tangentially located with respect to the outer surface of thebody 10 or they can also be skewed relative to the axis of body 10 in amanner that creates a swirl pattern in an uphole direction to push awaydebris as the fish that is not shown is brought out of the hole. Theorientation of the ports 30 can have one or more of the attributesdescribed above. They can be in a single row or multiple rows. They canbe equally spaced in multiple orientations or randomly spaced. They canbe all the same size and shape or different shapes or sizes. For runningin the seat 36 is in the FIG. 1 position and can be optionally retainedin that position by a breakable member such as a shear pin or ring, forexample. Optionally, the seat 36 can be made of a material thatdisintegrates or otherwise goes away with exposure to well conditions orthe passage of time to allow running in with ports 30 closed and passage18 open and at a later time after the fish is attached the ports 30 canopen with flow through passage 18 continuing. Preferably, the seat 36,which serves as a flow diverter, has a landing location 38 for asimilarly shaped object such as plug 40 shown in dashed lines. Itfurther has a through passage 23 to communicate with passage 22 whenplug 40 is not present. With plug 40 in position the passage 22 isisolated and the ports 30 are opened as the seat 36 shifts in tandemwith the plug 40 to open the ports 30. If there is a retainer, shownschematically as 42, it will be defeated with the force of fluidpressure on object 40. Optionally, object 40 can disintegrate with timeor exposure to well conditions as well as seat 36 if it is desired toreopen passage 22 on the way out of the hole with the fish that is notshown.

FIG. 2 illustrates a removable cap 42 used for protection when trippingin the hole to not expose a thread 44 that can be used in a differenttrip with cap 42 removed to mount various tools such as cut lip guide,washover shoe, muleshoe, wall hook guide and etc. With cap 42 in placethe fishing is done with only the magnets 16. As mentioned before theprotective cover 26 would also come off before the body 10 is run intothe borehole.

Those skilled in the art will appreciate that the magnetic fishing tooldescribed above has the capability to switch flow direction through itsbody so that going in the hole the flow is directed downwardly towardthe fish and after a grip is obtained the flow orientation can bereoriented to circulate out above the fish either laterally or in anuphole direction to keep debris fluidized ahead of the fish as the fishis brought out of the hole. It is preferable to cut off flow goingstraight through the tool with the fish engaged as that reduces thechances of the fish becoming dislodged from the tool on the way out ofthe hole. The magnets help with alignment of the body with the fish sothat a grip can be obtained by a tool connected near the magnets or by athread on the magnetic fishing tool engaging the fish directly. Thechange of flow configuration can also be accomplished in a variety ofways such as a pressure actuated indexing device that is capable ofopening ports 30 and closing them multiple times if it is necessary tochange the direction of the flow exiting body 10 more than once. Theflow diverter device can move axially or turn or both to redirect flowfrom axial to lateral or in an uphole direction. It can be moved with ashift tool or without well intervention. Different types of magnets canbe used although permanent magnets are preferred for simplicity and toavoid the provision of power to tool.

The above description is illustrative of the preferred embodiment andmany modifications may be made by those skilled in the art withoutdeparting from the invention whose scope is to be determined from theliteral and equivalent scope of the claims below:

We claim:
 1. A magnetic fishing tool for downhole use, comprising: abody comprising a through passage and at least one wall port; at leastone magnet mounted adjacent to a lower end of said body; a flow diverterin said passage for selectively directing flow between a first directiontoward said magnet and a second direction out said at least on wallport.
 2. The tool of claim 1, wherein: said flow diverter responsive topressure differential.
 3. The tool of claim 1, wherein: said throughpassage passing through said at least one magnet.
 4. The tool of claim1, wherein: said at least one wall port comprises multiple wall ports.5. The tool of claim 4, wherein: said wall ports oriented laterally to alongitudinal axis of said body or toward an uphole end of said body. 6.The tool of claim 4, wherein: said wall ports oriented to create aswirling fluid motion in a direction toward an uphole end of said body.7. The tool of claim 4, wherein: said ports are identical and equallyspaced.
 8. The tool of claim 4, wherein: said ports are different andrandomly spaced.
 9. The tool of claim 1, wherein: said flow diverterselectively retained in said passage against axial movement.
 10. Thetool of claim 1, wherein: said flow diverter formed to accept an objectto close off said passage to allow pressure buildup for opening said atleast one port.
 11. The tool of claim 1, wherein: said flow divertercapable of alternating flow between said first and second direction morethan once.
 12. The tool of claim 1, wherein: said at least one magnetcomprising a permanent magnet.
 13. The tool of claim 1, wherein: saidbody comprising an exterior thread adjacent a lower end thereof.
 14. Thetool of claim 1, further comprising: a removable protective cover forsaid body for use during shipping.
 15. The tool of claim 1, wherein: atleast a portion of said flow diverter disintegrates with exposure todownhole conditions or the passage of time.
 16. A fishing method fordownhole use, comprising: providing a through passage in a body and atleast one wall port; locating at least one magnet adjacent to a lowerend of said body; selectively directing flow, with a flow diverter insaid passage, between a first direction past said magnet on approach toa fish to be captured and a second direction out said at least on wallport as the fish is brought out of a downhole location.
 17. The methodof claim 16, wherein: operating said flow diverter responsive topressure differential.
 18. The method of claim 16, wherein: locatingsaid through passage through said at least one magnet.
 19. The method ofclaim 16, wherein: providing multiple wall ports as said at least onewall port.
 20. The method of claim 19, wherein: orienting said wallports laterally to a longitudinal axis of said body or toward an upholeend of said body.
 21. The method of claim 19, wherein: orienting saidwall ports to create a swirling fluid motion in a direction toward anuphole end of said body.
 22. The method of claim 19, wherein:configuring said ports identically and with equal spacing.
 23. Themethod of claim 19, wherein: configuring said ports differently and withrandom spacing.
 24. The method of claim 16, wherein: selectivelyretaining said flow diverter in said passage against axial movement. 25.The method of claim 16, wherein: forming said flow diverter to accept anobject to close off said passage to allow building pressure for openingsaid at least one port.
 26. The method of claim 16, wherein: alternatingflow in said flow diverter between said first and second direction morethan once.
 27. The method of claim 16, wherein: providing a permanentmagnet as said at least one magnet.
 28. The method of claim 16, wherein:locating an exterior thread adjacent a lower end of said body
 29. Themethod of claim 16, further comprising: covering said body duringshipping with a removable protective cover.
 30. The method of claim 16,wherein: disintegrating at least a portion of said flow diverter withexposure to downhole conditions or the passage of time.